It is known to form closures with end panels having buttons formed therein so as to indicate the condition of closure. Such closures include those in which the button is actuated by a vacuum condition within an associated container and those wherein the buttons are mechanically actuated when the closure is applied to a container under non-vacuum conditions.
It is also known to associate with the buttons of closures indicating means which will provide either a color indication or a display showing that the closure has been applied and then removed.